Book/Dissertation / PhD Thesis

FZJ-2017-08318

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Resistive switching memory devices fromatomic layer deposited binary and ternaryoxide thin films

Aslam, N. (Corresponding author)FZJ*

2017
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-274-0

Please use a persistent id in citations: http://hdl.handle.net/2128/16258

Abstract: Redox-based resistive switching memory (ReRAM) is rigorously investigated for next generation non-volatile storage devices, which comprise the new storage class memory(SCM) and realizations of logic in memory functions that aim towards the internet of things (IoT) and to neuromorphic computing. These applications require an aggressive downscaling of the energy consumption of the new memory devices as compared to actually used volatile dynamic random access memory (DRAM) or non-volatile Flash memory. ReRAM perfectly fits here due to its high energy efficiency, that means, low voltage operation, good endurance and stable retention at high integration density. The ReRAM function is based on the capability of certain metal/metal oxide/metal cells to change the resistance when electric stimuli are applied. For cell dimensions of a few 10 nm in each direction, the local uniformity of the resistive switching (RS) layer and its compositional homogeneity become an issue. So far, a lot of ReRAM research has been performed on rather thick (>25 nm) oxides grown by physical vapor deposition. For industrial application, atomic layer deposition (ALD) will be given priority because of its potential to grow ultrathin metal oxide films of high density and homogeneity with a conformal coverage. Most ALD oxide films are as grown in the amorphous state and crystallization heat treatment is performed prior to integration. However, for ultrathin (~10 nm) films there is rather limited information on compositional homogeneity after annealing. This effect is of particular importance for ternary thin films where the local cation (off-) stoichiometry might affect the microstructure and also the switching performance of the entire device. Highest integration density of ReRAM is achieved if the individual memristors are integrated into a passive crossbar array. However, sneak path currents through unselected cells neighbouring the switching cell put a severe restriction on the maximal achievable amount of cells in this array. Therefore, biploar-type selectors have to be added to each memristor. Selectors can be obtained from volatile threshold switches, like, for example, NbO$_{2}$, while the adjustment of the required phase is an issue. Inspired by the dynamics of the constantly growing ReRAM research this work deals with two oxidic materials where stoichiometries and phase formations play a crucial role. Both systems, namely strontium titanate (Sr$_{x}$Ti$_{y}$O$_{z}$ (short: STO)) and niobium oxide (Nb$_{2}$O$_{5}$/NbO$_{2}$), have been so far seldomly utilized in ReRAM devices when grown by [...]

Note: RWTH Aachen, Diss., 2017

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Contributing Institute(s):

1. Elektronische Materialien (PGI-7)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

Appears in the scientific report 2017

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Database coverage:
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